Our primary aim is to decipher the molecular and fine structural organization of living cells which are responsible for mitotic chromosome movement and related cell motility. We propose to tackle this problem through: (I) Polarization optical and related methods of quantitative light microscopy by which we can follow the state of molecular assemblies and ordered fine structure as they dynamically appear and change, directly in living cells and (II) continue to develop the instruments and new methods which make feasible these investigations on living cells in real time, as the cells divide normally or under the influence of altered physical, physiological or pharmacological conditions.